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NATURAL HISTORY

NORTH ATLANTIC RIGHT WHALE } Eubalaena glacialis
FAMILY: Balaenidae

DESCRIPTION: Robust and stocky with a gigantic mouth, the North Atlantic right whale is easily identifiable through its black coloration, lack of a dorsal fin, arched jaw that begins above the eye, and numerous light-colored growths on the head. Adult whales measure between 45 and 55 feet long and can weigh up to 70 tons.

HABITAT: Right whales prefer coastlines and large bays but also spend time in the open sea. They are very temperature sensitive, requiring temperatures of 13 to 15 degrees Celsius for successful calving. In addition, the availability of the plankton they eat depends heavily on ocean temperatures and circulation patterns, both of which may shift due to global warming.

RANGE: Historically, North Atlantic right whales occupied coastal and continental shelf waters in temperate subarctic latitudes on both sides of the Atlantic. Today, sightings are rare, with the highest observed concentrations occurring off coastal Florida, Georgia, and New England, depending on seasonal migration patterns. However, as survey effort has increased, it has become clear that right whales regularly use broader areas in the Northeast and Southeast, as well as their migratory corridor in mid-Atlantic U.S. waters.

MIGRATION: North Atlantic right whales calve during winter in the nearshore waters of the southeast U.S. coast. The majority of the population spends the summer in feeding and nursery grounds between New England and the Bay of Fundy. Most right whales migrate seasonally between these areas via mid-Atlantic coastal waters, traveling south in the fall and north in the spring.

BREEDING: Right whales first give birth at an average age of nine to 10 years and have a gestation period of approximately one year. Calves are generally born between December and March and are weaned at between eight and 17 months of age. At the current rate of reproduction, a female may give birth to between five and six calves over the course of her lifetime. Mating rituals and gestation times are believed to be similar to those of North Pacific right whales, with the whales nuzzling and caressing one another during courtship and an average gestation time of close to a year.

LIFE CYCLE: While there is some uncertainty about this whale’s life span, on average it is believed to be at least 50 years.

FEEDING: Right whales are baleen whales, meaning they use a comb-like strainer made of hundreds of long, narrow baleen plates attached to their upper jaws to filter large amounts of plankton. However, unlike other baleen whales, right whales are skimmers, feeding by continuously filtering food through their baleen while moving, mouth open, through patches of plankton.

THREATS: With estimates indicating that there are fewer than 400 individuals remaining, the North Atlantic right whale is very vulnerable to a variety of manmade threats. The greatest known causes of North Atlantic right whale mortality are collisions with ships and entanglement in commercial fishing gear. The whales also face threats from habitat degradation, industrial pollution, climate change, and military activities in the form of noise pollution and underwater explosions.

POPULATION TREND: Like the North Pacific right whale, the North Atlantic right whale was once subject to such intensive commercial hunting that its population was severely depleted by the late 1600s. With fewer than 400 individuals now remaining, it is estimated that the North Atlantic right whale will be extinct within three to four generations without serious intervention. Sadly, the eastern North Atlantic population is believed to be functionally extinct. Every individual counts in this population, and saving just two more female right whales per year could make the difference between extinction and recovery.

North Atlantic right whale photo courtesy NOAA